LSF Version 7.3 - Administering Platform LSF

Administering Platform LSF 175
Platform LSF Licensing
Floating Client Licenses
LSF floating client is valuable if you have a cluster in which not all of the hosts will
be active at the same time. In this section, you will learn how to save money through
distributing your licenses efficiently.
An LSF floating client license is a type of LSF license to be shared among several
client hosts at different times. Floating client licenses are not tied to specific hosts.
They are assigned dynamically to any host that submits a request to LSF. The
number of licenses acts as a license pool for the cluster from which LSF clients can
draw required licenses. Although floating client licenses are supported, LSF does
not support floating server licenses.
Client hosts and floating client hosts
In LSF, you can have both client hosts and floating client hosts. The difference is in
the type of license purchased.
If you purchased a regular (fixed) client license, LSF client hosts are static. The
client hosts must be listed in
lsf.cluster.cluster_name. The license is fixed to the
hosts specified in
lsf.cluster.cluster_name and whenever client hosts change,
you must update it with the new host list.
If you purchased a floating client license, LSF floating client hosts are dynamic.
They are not listed in
lsf.cluster.cluster_name. Since LSF does not take into
account the host name but the number of floating licenses, clients can change
dynamically and licenses will be distributed to clients that request to use LSF. When
you submit a job from any unlicensed host, and if there are any floating licenses
free, the host will check out a license and submit your job to LSF. However, once a
host checks out a floating client license, it keeps that license for the rest of the day,
until midnight. A host that becomes a floating client behaves like a fixed client all
day, then at 12 midnight it releases the license. At that time, the host turns back into
a normal, unlicensed host, and the floating client license becomes available to any
other host that needs it.
How floating licenses work in LSF
Read this to understand how floating licenses work. You will want to read this
before configuring your cluster to use this distribution technique.
When the master LIM starts up, it verifies how many floating licenses there are for
the cluster as specified in
lsf.cluster.cluster_name with the parameter
FLOAT_CLIENTS. The master LIM checks out the licenses and keeps track of
license information—how many floating licenses have been assigned, and which
client hosts are using the licenses.
Floating client licenses expire at midnight (local time) on the day the license was
issued. The master LIM checks the host list and removes any floating client hosts
whose license has expired.
License reset Whenever the master LIM is restarted, all LSF floating client licenses are released
and checked out again.